Warnings come in leaflet, voice and text messages tellling civilians to avoid
areas being used by militants

Israel issued an ominous warning to the people of Gaza to expect further intensified bombardments after Benjamin Netanyahu vowed to make Hamas “pay a heavy price” for killing a four-year-old Israeli boy in a mortar attack.

Messages issued by leaflet, voice mail and text warned civilians to avoid places being used by known militants and seemed to presage a further escalation after nearly seven weeks of warfare that has already left more than 2,000 people dead.

“Every house from which militant activity is carried out will be targeted,” said the messages, addressed to “the residents of Gaza”.

“For your own safety, prevent terrorists from utilising your property for terror agendas, and stay away from every site in which terrorist organisations are operating. The IDF calls you to distance yourselves from where fire was directed at Israel.”

The warnings were issued after Israeli missiles had hit at least 20 targets early on Saturday - including a strike that destroyed a house in the central Gaza town of Al-Zawayda, killing five members of one Palestinian family, among them two children aged three and four.

That followed the death on Friday of Daniel Tregerman, the first Israeli child to die in the 47-day conflict. He suffered fatal shrapnel wounds after a mortar shell landed next to his home in Nahal Oz, a kibbutz close to the Gaza border.

Palestinian children flee from their home as Palestinian firefighters tackle a fire in the house after Israeli air strikes on Gaza

In an emotional response, Mr Netanyahu, the Israeli prime minister, said: “Hamas will pay a heavy price for this terrible terrorist attack. The IDF [the Israeli Defence Forces] and the Shin Bet [the domestic intelligence agency] will intensify their operations against Hamas and the terrorist organisations in Gaza until the goals of Operation Protective Edge are reached.”

The shell that killed Daniel was among 100 missiles fired from Gaza into Israel on Friday, according to the Israeli military, which said militants had launched around 500 projectiles since the collapse of a nine-day ceasefire last Tuesday. A funeral for the dead boy will be held on Sunday.

His mother, Gila, said the family had been preparing to leave the kibbutz due to the barrage of missiles at the time of the attack, having returned only a few days before when General Benny Gantz, the Israeli army chief-of-staff, declared it safe.

Despite his tender years, Daniel already knew to go to the bomb shelter that is obligatory in every Israeli home when warning sirens sounded for incoming missiles, said Mrs Tregerman. But on this occasion he could not get there on time.

“The children were playing in a tent inside the house, and from the moment of the siren to the explosion only three seconds passed ,” she told Ynet, an Israeli news website. “We didn’t have time to get the children and go into the protected room.”

A picture of the dead boy wearing an Argentina football shirt sparked an Israeli social media campaign calling on Lionel Messi, the Barcelona superstar who was said to be Daniel’s hero, to condemn the killing.

Ynet pointed out that Messi had recently expressed sorrow at the images of dead and injured Palestinian children on his official Facebook page, citing his role as an ambassador for Unicef, the United Nations’ children’s charity.

“I am terribly saddened by the images coming from the conflict between Israel and Palestine, where violence has already claimed so many young lives and to injure countless children. This cycle of senseless violence must stop,” he wrote in a post illustrated with a picture of an injured Palestinian child.

The Israeli army initially claimed the missile that killed Daniel was fired from an area beside one of 84 UN schools currently housing more than 292,000 homeless Palestinians after being converted into emergency shelters. It later amended its assessment, saying that the shelter in Gaza City’s Zeitoun area was run by Hamas.

There have been three deadly strikes on UN shelters during the current conflict, killing a total of 36 Palestinians - many of them children - and drawing widespread international condemnation that has mostly been aimed at Israel.

Some 480 children, aged from 10 days to 17 years, have died since hostilities started on July 8, according to Unicef. Eight Palestinian children were killed throughout Gaza in the 48 hours before 8am yesterday SATURDAY morning, the charity said.

At least 2,097 Palestinians of all ages had died by Saturday, according to Gaza health agencies. The Israeli death toll is 68, all but four of them soldiers.

As the conflict continued to rage without any sign of ending, Egypt urged both sides to accept an open-ended ceasefire and return to indirect negotiations, which collapsed last week.

The plea came after a meeting in Cairo between Abdel Fattah al-Sisi, the Egyptian president, and Mahmoud Abbas, the Palestinian Authority president, who also supported the ceasefire call. Mr Abbas’ plea for a ceasefire followed meetings in Qatar last week with Khaled Meshaal, the Hamas hardliner who is the organisation’s leader-in-exile.

In an earlier interview with Yahoo News, Mr Meshaal pledged that Hamas would strike only military targets in future if it obtained “better weapons”, thus avoiding killing Israeli civilians. He also admitted that members of the Islamist group’s military wing had abducted and murdered three Israeli teenagers in the West Bank in June but said Hamas leaders had not known of the plan beforehand.